The modern method for producing multi-view images on the basis of integral Lippmann photography provides that several views (usually starting with 12) of a 3D object or a scene are taken by one or several photo apparatuses from several points by the aid of computer are cut into narrow strips and alternates in inverted order with the period equal to a lenticular pitch. Plastic film with lenticular lens array is usually used as lens pattern. At present this method is broadly spread due to the computer synthesis of elemental images array, the development of means of high-resolution print and the progress in producing of high-pitch microlens arrays in the form of optical films and plastic sheets.
Disadvantages of this method are rather low resolution and a small depth of field of multi-view images, and the requirement of extreme accuracy to align the pitch of lenticular lens and elemental images array, and proportional increase of consumption of optical materials when manufacturing lens arrays with the lens elements of larger size. The number of lens elements per inch in optical films used for producing multi-view images should be at least 12 times less than the number per inch of separately discernible elements in elemental images. For example, in order to produce a high quality multi-view image by microlens array with the number of lens elements per inch equal to 200, a resolution of elemental images output device shall be approximately 6000 points per inch. Superposition accuracy of elemental images and microlens array shall not exceed 1/200 inch. At present these requirements are difficult to implement.
There is known the method for producing multi-view image described in U.S. Pat. No. 7,457,039, wherein at an outer side of a wall of an optically transparent container, for example, plastic packaging, the optical film is arranged that comprises an array of positive lenticular lenses with the period mainly from 70 to 20 microlens per inch, and at the opposite side of the wall of the optically transparent container the elemental images array is arranged in such a way that focal points of each of the microlenses are situated at the same distance from the surface of optical film that an interlaced image is (elemental image array analogue), or in close proximity to it. Due to the substitution of a part of the thickness of the optical film for optically transparent material this method allows decreasing the thickness of the optical film not increasing the number of microlenses per inch.
The disadvantage of the known method is the increase of visibility of lens elements for a viewer in proportion to the decrease of the number of microlenses per inch, and the dependency relation between the thickness of the optical film and relationship of the number of microlenses and a microlens curvature R, that does not allow increasing the size and the viewing angle in wide range without a proportional increase of the thickness of the optical film.
One of a possible solution may be a substitution of convex lens elements for plane substitutes thereof, for example, by Fresnel lenses that allows increasing in a wider range the size of lens elements not increasing the thickness of the optical film. However, the multi-view image created with the use of Fresnel lens array looks segmented one, and the boundaries between separate lens elements of an array are well seen for a viewer.
A superlens, a principle of creation of which is described by Gabor in the patent GB541753A, as well as Fresnel lens, is a plane substitute of a convex lens. One of the main features of Gabor superlenses compared to other plane lenses is that there are no well-defined boundaries in the superlens array between separate superlenses—they gradually change from one to another. The disadvantage of superlens array described in GB541753A, when used instead of convex lens array for producing multi-view images, is that at a significant decrease of focal length of superlenses obtained by a focal superposition of two arrays of spherical or cylindrical microlenses, a spherical aberration and light transmittance irregularity in a paraxial and peripheral regions of the superlenses are increased. This makes separate superlenses more noticeable for a viewer, and result in quality degradation of the multi-view image.
In GB541753A described are the variants of creation of superlenses with decreased spherical aberration. One of the variant of creation of superlenses with decreased spherical aberration described in GB541753A, comprises afocal superposition of two cylindrical (lenticular) or spherical (fly-eye) microlenses made of optically transparent materials with essentially different refractive indices. The disadvantage of this variant is that two different optical materials with maximum and minimum refractive indices, and additional adhesive layers shall be used, for superposition of these materials. The method of manufacturing such a film is expensive and technically complex one. Another variant involves the use of aplanatic microlens arrays for creation of superlenses. This requires additional optical layers in both microlens arrays that is difficult to implement from technical point of view. Another variant of decrease of spherical aberration involves superlens diaphragming. Diaphragming is not desirable because a noticeability of separate superlenses for a viewer is increased.